Added PlayerPurchaseEvent for standalone Merchant GUIs (#5583)

2021-05-24 11:51:06 +01:00 · 2021-05-24 11:51:06 +01:00 · afe0785bfe
Commit afe0785bfe
--- a/Spigot-API-Patches/0244-added-PlayerTradeEvent.patch
+++ b/Spigot-API-Patches/0244-added-PlayerTradeEvent.patch
@ -1,78 +1,75 @@
 From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
 From: Jake Potrebic <jake.m.potrebic@gmail.com>
 Date: Thu, 2 Jul 2020 16:10:10 -0700
-Subject: [PATCH] added PlayerTradeEvent
+Subject: [PATCH] Added PlayerTradeEvent

+[Amendment: Alexander <protonull@protonmail.com>]
+PlayerTradeEvent is used for player purchases from villagers and wandering
+traders, but not custom merchants created via Bukkit.createMerchant(). During
+discussions in Discord it was decided that it'd be better to add a new event
+that PlayerTradeEvent inherits from than change getVillager()'s annotation to
+@Nullable, especially since that'd also infringe on the implication of the
+event being about villager trades.

-diff --git a/src/main/java/io/papermc/paper/event/player/PlayerTradeEvent.java b/src/main/java/io/papermc/paper/event/player/PlayerTradeEvent.java
-new file mode 100755
-index 0000000000000000000000000000000000000000..198e5464eae6b961c83148a57c18f91a4bb33cf6
+diff --git a/src/main/java/io/papermc/paper/event/player/PlayerPurchaseEvent.java b/src/main/java/io/papermc/paper/event/player/PlayerPurchaseEvent.java
+new file mode 100644
+index 0000000000000000000000000000000000000000..c5648055c5e815474bf1e564a5c192ff5c0624fb
 --- /dev/null
-+++ b/src/main/java/io/papermc/paper/event/player/PlayerTradeEvent.java
-@@ -0,0 +1,121 @@
+++ b/src/main/java/io/papermc/paper/event/player/PlayerPurchaseEvent.java
+@@ -0,0 +1,112 @@
 +package io.papermc.paper.event.player;
 +
-+import org.bukkit.entity.AbstractVillager;
+import java.util.Objects;
 +import org.bukkit.entity.Player;
 +import org.bukkit.event.Cancellable;
 +import org.bukkit.event.HandlerList;
 +import org.bukkit.event.player.PlayerEvent;
 +import org.bukkit.inventory.MerchantRecipe;
 +import org.jetbrains.annotations.NotNull;
-+import org.jetbrains.annotations.Nullable;
 +
 +/**
-+ * Called when a player trades with a villager or wandering trader
+ * Called when a player trades with a standalone merchant GUI.
 + */
-+public class PlayerTradeEvent extends PlayerEvent implements Cancellable {
-+
+public class PlayerPurchaseEvent extends PlayerEvent implements Cancellable {
 +    private static final HandlerList handlers = new HandlerList();
 +    private boolean cancelled;
 +
 +    private boolean increaseTradeUses;
 +    private boolean rewardExp;
-+    private final AbstractVillager villager;
 +    private MerchantRecipe trade;
 +
-+    public PlayerTradeEvent(@NotNull Player player, @NotNull AbstractVillager villager, @NotNull MerchantRecipe trade, boolean rewardExp, boolean increaseTradeUses) {
-+        super(player);
-+        this.villager = villager;
-+        this.trade = trade;
+    public PlayerPurchaseEvent(@NotNull Player player,
+                               @NotNull MerchantRecipe trade,
+                               boolean rewardExp,
+                               boolean increaseTradeUses) {
+        super(Objects.requireNonNull(player, "Player cannot be null!"));
+        setTrade(trade);
 +        this.rewardExp = rewardExp;
 +        this.increaseTradeUses = increaseTradeUses;
 +    }
 +
 +    /**
-+     * Gets the Villager or Wandering trader associated with this event
-+     * @return the villager or wandering trader
-+     */
-+    @NotNull
-+    public AbstractVillager getVillager() {
-+        return villager;
-+    }
-+
-+    /**
 +     * Gets the associated trade with this event
 +     * @return the trade
 +     */
 +    @NotNull
 +    public MerchantRecipe getTrade() {
-+        return trade;
+        return this.trade;
 +    }
 +
 +    /**
 +     * Sets the trade. This is then used to determine the next prices
 +     * @param trade the trade to use
 +     */
-+    public void setTrade(@Nullable MerchantRecipe trade) {
-+        this.trade = trade;
+    public void setTrade(@NotNull MerchantRecipe trade) {
+        this.trade = Objects.requireNonNull(trade, "Trade cannot be null!");
 +    }
 +
 +    /**
 +     * @return will trade try to reward exp
 +     */
 +    public boolean isRewardingExp() {
-+        return rewardExp;
+        return this.rewardExp;
 +    }
 +
 +    /**
@ -87,7 +84,7 @@ index 0000000000000000000000000000000000000000..198e5464eae6b961c83148a57c18f91a
 +     * @return whether or not the trade will count as a use of the trade
 +     */
 +    public boolean willIncreaseTradeUses() {
-+        return increaseTradeUses;
+        return this.increaseTradeUses;
 +    }
 +
 +    /**
@ -130,4 +127,40 @@ index 0000000000000000000000000000000000000000..198e5464eae6b961c83148a57c18f91a
 +    public static HandlerList getHandlerList() {
 +        return handlers;
 +    }
+
+}
+diff --git a/src/main/java/io/papermc/paper/event/player/PlayerTradeEvent.java b/src/main/java/io/papermc/paper/event/player/PlayerTradeEvent.java
+new file mode 100755
+index 0000000000000000000000000000000000000000..a41fc186746b87f76347dfcc1f80d0969398322b
+--- /dev/null
+++ b/src/main/java/io/papermc/paper/event/player/PlayerTradeEvent.java
+@@ -0,0 +1,29 @@
+package io.papermc.paper.event.player;
+
+import org.bukkit.entity.AbstractVillager;
+import org.bukkit.entity.Player;
+import org.bukkit.inventory.MerchantRecipe;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Called when a player trades with a villager or wandering trader
+ */
+public class PlayerTradeEvent extends PlayerPurchaseEvent {
+
+    private final AbstractVillager villager;
+
+    public PlayerTradeEvent(@NotNull Player player, @NotNull AbstractVillager villager, @NotNull MerchantRecipe trade, boolean rewardExp, boolean increaseTradeUses) {
+        super(player, trade, rewardExp, increaseTradeUses);
+        this.villager = villager;
+    }
+
+    /**
+     * Gets the Villager or Wandering trader associated with this event
+     * @return the villager or wandering trader
+     */
+    @NotNull
+    public AbstractVillager getVillager() {
+        return this.villager;
+    }
+
 +}
--- a/Spigot-Server-Patches/0743-Have-CraftMerchantCustom-emit-PlayerPurchaseEvent.patch
+++ b/Spigot-Server-Patches/0743-Have-CraftMerchantCustom-emit-PlayerPurchaseEvent.patch
@ -0,0 +1,59 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Alexander <protonull@protonmail.com>
+Date: Thu, 6 May 2021 13:01:25 +0100
+Subject: [PATCH] Have CraftMerchantCustom emit PlayerPurchaseEvent
+
+
+diff --git a/src/main/java/net/minecraft/world/item/trading/IMerchant.java b/src/main/java/net/minecraft/world/item/trading/IMerchant.java
+index 5644affeadc51ac3209ee9a087b3d2dd887e401c..7c54ca6af424b9d31f73187df9015f5df84762f4 100644
+--- a/src/main/java/net/minecraft/world/item/trading/IMerchant.java
+++ b/src/main/java/net/minecraft/world/item/trading/IMerchant.java
+@@ -19,7 +19,7 @@ public interface IMerchant {
+ 
+     MerchantRecipeList getOffers();
+ 
+-    void a(MerchantRecipe merchantrecipe);
+    void a(MerchantRecipe merchantrecipe); default void handlePurchase(MerchantRecipe merchantRecipe) { a(merchantRecipe); } // Paper - OBFHELPER
+ 
+     void k(ItemStack itemstack);
+ 
+diff --git a/src/main/java/org/bukkit/craftbukkit/inventory/CraftMerchantCustom.java b/src/main/java/org/bukkit/craftbukkit/inventory/CraftMerchantCustom.java
+index 206c133ebc6c44038585236b0628543b8bed278c..a7230776b8e85d5d1873ab2dc4e10c5bf78889bb 100644
+--- a/src/main/java/org/bukkit/craftbukkit/inventory/CraftMerchantCustom.java
+++ b/src/main/java/org/bukkit/craftbukkit/inventory/CraftMerchantCustom.java
+@@ -81,6 +81,35 @@ public class CraftMerchantCustom extends CraftMerchant {
+ 
+         @Override
+         public void a(MerchantRecipe merchantrecipe) {
+            // Paper start
+            /** Based on {@link net.minecraft.world.entity.npc.EntityVillagerAbstract#b(MerchantRecipe)} */
+            if (getTrader() instanceof net.minecraft.server.level.EntityPlayer) {
+                final net.minecraft.server.level.EntityPlayer trader = (net.minecraft.server.level.EntityPlayer) getTrader();
+                final io.papermc.paper.event.player.PlayerPurchaseEvent event = new io.papermc.paper.event.player.PlayerPurchaseEvent(
+                    trader.getBukkitEntity(),
+                    merchantrecipe.asBukkit(),
+                    false, // reward xp?
+                    true); // should increase uses?
+                event.callEvent();
+                if (event.isCancelled()) {
+                    return;
+                }
+                final org.bukkit.inventory.MerchantRecipe eventTrade = event.getTrade();
+                if (event.willIncreaseTradeUses()) {
+                    eventTrade.setUses(eventTrade.getUses() + 1);
+                }
+                if (event.isRewardingExp() && eventTrade.hasExperienceReward()) {
+                    /** Based on {@link net.minecraft.world.entity.npc.EntityVillagerTrader#b(MerchantRecipe)} */
+                    final int xp = 3 + net.minecraft.world.entity.Entity.SHARED_RANDOM.nextInt(4);
+                    final World world = trader.getWorld();
+                    world.addEntity(new net.minecraft.world.entity.EntityExperienceOrb(
+                        world, trader.locX(), trader.locY() + 0.5d, trader.locZ(), xp,
+                        org.bukkit.entity.ExperienceOrb.SpawnReason.VILLAGER_TRADE, trader, null));
+                }
+                return;
+            }
+            // Paper end
+
+             // increase recipe's uses
+             merchantrecipe.increaseUses();
+         }